نتایج جستجو برای: distribution of frequency

تعداد نتایج: 21222023  

Identification of the vertical and horizontal distributions for elemental grades is of an important sign in different mineral exploration stages. The main aim of this work is to determine the vertical distribution directional properties of Cu values in the Milloieh Cu porphyry deposit, Kerman (SE Iran) using the power-law frequency fractal model. This work is carried out based on four mineraliz...

2004

Heart sounds and murmurs are timevarying signals that would best be analyzed using timefrequency analysis. Windowed Wigner-Ville distribution (WWVD) and smooth windowed Wigner-Vffle distribution (SWWVD) are used to obtain the timefrequency representation of the signal. Determination of parameter setting of WWVD and SWWVD will eliminate the cross-terms and improve time frequency representation. ...

Journal: :desert 2012
a.r. keshtkar a. salajegheh m. najafi hajivar

statistical frequency analysis is the most common procedure for the analysis of flood data at a gauged location thatin first step it is needed to select a model to represent the population. among them, the central moment has been themost common and widely used, and with the using of computers, the application of the maximum likelihood hasincreased. this research was carried out in order to reco...

Journal: :the modares journal of electrical engineering 2012
elham amini boroujeni hamid reza momeni mahdi sojoodi

non-fragile observer design is the main problem of this paper. using continuous frequency distribution, the stability conditions based on integer order lyapunov theorem are derived for lipschitz class of nonlinear fractional order systems. the proposed observer is stable beside the existence of both gain perturbation and input disturbance. for the first time, in this paper a systematic method i...

Journal: :EURASIP J. Adv. Sig. Proc. 2010
Omid Talakoub Jie Cui Willy Wong

A new member of the Cohen’s class time-frequency distribution is proposed. The kernel function is determined adaptively based on the signal of interest. The kernel preserves the chirp-like components while removing interference terms generated due to the quadratic characteristic of Wigner-Ville distribution. This approach is based on the chirplet as an underlying model of biomedical signals. We...

پایان نامه :دانشگاه آزاد اسلامی واحد علوم پزشکی تهران - دانشکده پزشکی 1389

مقدمه: فرکتالها عبارتند از ساختارهای هندسی پیچیده. علم فرکتال که به بررسی این ساختارها می پردازد در سال 1975 ابداع گردید و امروزه نه تنها در علوم مهندسی بلکه در علوم پزشکی نیز جایگاه ویژه ای یافته است. فرکتال ها در تشخیص بیماری های استخوانی و مدل سازی ساختار استخوانها و تحلیل تغییرات ساختار آنها و تحلیل ریتم و ضربان قلب و تشخیص بیماری های قلبی کاربرد دارند. هرچند به نظر می رسد هرکجا که یک بی نظ...

Journal: :IEEE Trans. Signal Processing 1994
Shie Qian Dapang Chen

1998
Jeffrey C. O'Neill William J. Williams

Cohen’s class of time-frequency distributions for continuous signals has recently been to extended to discrete signals using both an axiomatic approach and an operator theory approach. In this paper, we investigate the formulation of several classical timefrequency distributions (Wigner, Rihaczek, Margenau-Hill, Page, Levin, Born-Jordan, spectrogram) in the discrete Cohen’s classes. The main re...

Journal: :تحقیقات جغرافیایی 0
مژده پدرام هوشنگ قائمی هوشنگ قائمی اکرم هدایت دزفولی افسانه مرتضوی

â  in order to determine the snowfall threshold temperature in different regions of kurdistan province, first the occurrence times of the non shower snow, associated with dry-bulb temperature and dew point temperature at the time of observation were extracted for 7 synoptic stations of the province. then, the frequency, relative frequency and cumulative frequency of snowfall in different temper...

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